blockd.c

   1 #define _GNU_SOURCE
   2 #include <sys/stat.h>
   3 #include <sys/mount.h>
   4 #include <sys/wait.h>
   5
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <fcntl.h>
  10
  11 #include <errno.h>
  12
  13 #include <linux/limits.h>
  14 #include <linux/auto_fs4.h>
  15
  16 #include <libubox/uloop.h>
  17 #include <libubox/vlist.h>
  18 #include <libubox/ulog.h>
  19 #include <libubox/avl-cmp.h>
  20 #include <libubus.h>
  21
  22 #include "libfstools/libfstools.h"
  23
  24 #define AUTOFS_MOUNT_PATH       "/tmp/run/blockd/"
  25 #define AUTOFS_TIMEOUT          30
  26 #define AUTOFS_EXPIRE_TIMER     (5 * 1000)
  27
  28 struct hotplug_context {
  29         struct uloop_process process;
  30         void *priv;
  31 };
  32
  33 struct device {
  34         struct vlist_node node;
  35         struct blob_attr *msg;
  36         char *name;
  37         char *target;
  38         int autofs;
  39         int anon;
  40 };
  41
  42 static struct uloop_fd fd_autofs_read;
  43 static int fd_autofs_write = 0;
  44 static struct ubus_auto_conn conn;
  45 struct blob_buf bb = { 0 };
  46
  47 enum {
  48         MOUNT_UUID,
  49         MOUNT_LABEL,
  50         MOUNT_ENABLE,
  51         MOUNT_TARGET,
  52         MOUNT_DEVICE,
  53         MOUNT_OPTIONS,
  54         MOUNT_AUTOFS,
  55         MOUNT_ANON,
  56         MOUNT_REMOVE,
  57         __MOUNT_MAX
  58 };
  59
  60 static const struct blobmsg_policy mount_policy[__MOUNT_MAX] = {
  61         [MOUNT_UUID] = { .name = "uuid", .type = BLOBMSG_TYPE_STRING },
  62         [MOUNT_LABEL] = { .name = "label", .type = BLOBMSG_TYPE_STRING },
  63         [MOUNT_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
  64         [MOUNT_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
  65         [MOUNT_OPTIONS] = { .name = "options", .type = BLOBMSG_TYPE_STRING },
  66         [MOUNT_ENABLE] = { .name = "enabled", .type = BLOBMSG_TYPE_INT32 },
  67         [MOUNT_AUTOFS] = { .name = "autofs", .type = BLOBMSG_TYPE_INT32 },
  68         [MOUNT_ANON] = { .name = "anon", .type = BLOBMSG_TYPE_INT32 },
  69         [MOUNT_REMOVE] = { .name = "remove", .type = BLOBMSG_TYPE_INT32 },
  70 };
  71
  72 enum {
  73         INFO_DEVICE,
  74         __INFO_MAX
  75 };
  76
  77 static const struct blobmsg_policy info_policy[__INFO_MAX] = {
  78         [INFO_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
  79 };
  80
  81 static char*
  82 _find_mount_point(char *device)
  83 {
  84         char *dev, *mp;
  85
  86         if (asprintf(&dev, "/dev/%s", device) == -1)
  87                 exit(ENOMEM);
  88
  89         mp = find_mount_point(dev, 0);
  90         free(dev);
  91
  92         return mp;
  93 }
  94
  95 static int
  96 block(char *cmd, char *action, char *device)
  97 {
  98         pid_t pid = fork();
  99         int ret = -1;
 100         int status;
 101         char *argv[5] = { 0 };
 102         int a = 0;
 103
 104         switch (pid) {
 105         case -1:
 106                 ULOG_ERR("failed to fork block process\n");
 107                 break;
 108
 109         case 0:
 110                 argv[a++] = "/sbin/block";
 111                 argv[a++] = cmd;
 112                 argv[a++] = action;
 113                 argv[a++] = device;
 114                 execvp(argv[0], argv);
 115                 ULOG_ERR("failed to spawn %s %s %s\n", *argv, action, device);
 116                 exit(EXIT_FAILURE);
 117
 118         default:
 119                 waitpid(pid, &status, 0);
 120                 ret = WEXITSTATUS(status);
 121                 if (ret)
 122                         ULOG_ERR("failed to run block. %s/%s\n", action, device);
 123                 break;
 124         }
 125
 126         return ret;
 127 }
 128
 129 static int hotplug_call_mount(const char *action, const char *devname,
 130                               uloop_process_handler cb, void *priv)
 131 {
 132         char * const argv[] = { "hotplug-call", "mount", NULL };
 133         struct hotplug_context *c = NULL;
 134         pid_t pid;
 135         int err;
 136
 137         if (cb) {
 138                 c = calloc(1, sizeof(*c));
 139                 if (!c)
 140                         return -ENOMEM;
 141         }
 142
 143         pid = fork();
 144         switch (pid) {
 145         case -1:
 146                 err = -errno;
 147                 ULOG_ERR("fork() failed\n");
 148                 return err;
 149         case 0:
 150                 uloop_end();
 151
 152                 setenv("ACTION", action, 1);
 153                 setenv("DEVICE", devname, 1);
 154
 155                 execv("/sbin/hotplug-call", argv);
 156                 exit(-1);
 157                 break;
 158         default:
 159                 if (c) {
 160                         c->process.pid = pid;
 161                         c->process.cb = cb;
 162                         c->priv = priv;
 163                         uloop_process_add(&c->process);
 164                 }
 165                 break;
 166         }
 167
 168         return 0;
 169 }
 170
 171 static void device_mount_remove_hotplug_cb(struct uloop_process *p, int stat)
 172 {
 173         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 174         struct device *device = hctx->priv;
 175         char *mp;
 176
 177         if (device->target)
 178                 unlink(device->target);
 179
 180         mp = _find_mount_point(device->name);
 181         if (mp) {
 182                 block("autofs", "remove", device->name);
 183                 free(mp);
 184         }
 185
 186         free(device);
 187         free(hctx);
 188 }
 189
 190 static void device_mount_remove(struct device *device)
 191 {
 192         hotplug_call_mount("remove", device->name,
 193                            device_mount_remove_hotplug_cb, device);
 194 }
 195
 196 static void device_mount_add(struct device *device)
 197 {
 198         struct stat st;
 199         char *path;
 200
 201         if (asprintf(&path, "/tmp/run/blockd/%s", device->name) == -1)
 202                 exit(ENOMEM);
 203
 204         if (!lstat(device->target, &st)) {
 205                 if (S_ISLNK(st.st_mode))
 206                         unlink(device->target);
 207                 else if (S_ISDIR(st.st_mode))
 208                         rmdir(device->target);
 209         }
 210         if (symlink(path, device->target))
 211                 ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device->target, path, errno);
 212         else
 213                 hotplug_call_mount("add", device->name, NULL, NULL);
 214
 215         free(path);
 216 }
 217
 218 static int
 219 device_move(struct device *device_o, struct device *device_n)
 220 {
 221         char *path;
 222
 223         if (device_o->autofs != device_n->autofs)
 224                 return -1;
 225
 226         if (device_o->anon || device_n->anon)
 227                 return -1;
 228
 229         if (device_o->autofs) {
 230                 unlink(device_o->target);
 231                 if (asprintf(&path, "/tmp/run/blockd/%s", device_n->name) == -1)
 232                         exit(ENOMEM);
 233
 234                 if (symlink(path, device_n->target))
 235                         ULOG_ERR("failed to symlink %s->%s (%d) - %m\n", device_n->target, path, errno);
 236
 237                 free(path);
 238         } else {
 239                 mkdir(device_n->target, 0755);
 240                 if (mount(device_o->target, device_n->target, NULL, MS_MOVE, NULL))
 241                         rmdir(device_n->target);
 242                 else
 243                         rmdir(device_o->target);
 244         }
 245
 246         return 0;
 247 }
 248
 249 static void vlist_nop_update(struct vlist_tree *tree,
 250                              struct vlist_node *node_new,
 251                              struct vlist_node *node_old)
 252 {
 253 }
 254
 255 VLIST_TREE(devices, avl_strcmp, vlist_nop_update, false, false);
 256
 257 static int
 258 block_hotplug(struct ubus_context *ctx, struct ubus_object *obj,
 259               struct ubus_request_data *req, const char *method,
 260               struct blob_attr *msg)
 261 {
 262         struct blob_attr *data[__MOUNT_MAX];
 263         struct device *device;
 264         struct blob_attr *_msg;
 265         char *devname, *_name;
 266         char *target = NULL, *__target;
 267         char *_target = NULL;
 268
 269         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 270
 271         if (!data[MOUNT_DEVICE])
 272                 return UBUS_STATUS_INVALID_ARGUMENT;
 273
 274         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 275
 276         if (data[MOUNT_TARGET]) {
 277                 target = blobmsg_get_string(data[MOUNT_TARGET]);
 278         } else {
 279                 if (asprintf(&_target, "/mnt/%s",
 280                              blobmsg_get_string(data[MOUNT_DEVICE])) == -1)
 281                         exit(ENOMEM);
 282
 283                 target = _target;
 284         }
 285
 286         if (data[MOUNT_REMOVE])
 287                 device = vlist_find(&devices, devname, device, node);
 288         else
 289                 device = calloc_a(sizeof(*device), &_msg, blob_raw_len(msg),
 290                                   &_name, strlen(devname) + 1, &__target, strlen(target) + 1);
 291
 292         if (!device) {
 293                 if (_target)
 294                         free(_target);
 295
 296                 return UBUS_STATUS_UNKNOWN_ERROR;
 297         }
 298
 299         if (data[MOUNT_REMOVE]) {
 300                 vlist_delete(&devices, &device->node);
 301
 302                 if (device->autofs)
 303                         device_mount_remove(device);
 304                 else
 305                         free(device);
 306
 307                 if (_target)
 308                         free(_target);
 309         } else {
 310                 struct device *old = vlist_find(&devices, devname, device, node);
 311
 312                 device->autofs = data[MOUNT_AUTOFS] ? blobmsg_get_u32(data[MOUNT_AUTOFS]) : 0;
 313                 device->anon = data[MOUNT_ANON] ? blobmsg_get_u32(data[MOUNT_ANON]) : 0;
 314                 device->msg = _msg;
 315                 memcpy(_msg, msg, blob_raw_len(msg));
 316                 device->name = _name;
 317                 strcpy(_name, devname);
 318                 device->target = __target;
 319                 strcpy(__target, target);
 320                 if (_target)
 321                         free(_target);
 322
 323                 vlist_add(&devices, &device->node, device->name);
 324
 325                 if (old && !device_move(old, device)) {
 326                         if (device->autofs) {
 327                                 device_mount_remove(old);
 328                                 device_mount_add(device);
 329                         } else {
 330                                 block("mount", NULL, NULL);
 331                         }
 332                 } else if (device->autofs) {
 333                         device_mount_add(device);
 334                 }
 335         }
 336
 337         return 0;
 338 }
 339
 340 static int blockd_mount(struct ubus_context *ctx, struct ubus_object *obj,
 341                         struct ubus_request_data *req, const char *method,
 342                         struct blob_attr *msg)
 343 {
 344         struct blob_attr *data[__MOUNT_MAX];
 345         struct device *device;
 346         char *devname;
 347
 348         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 349
 350         if (!data[MOUNT_DEVICE])
 351                 return UBUS_STATUS_INVALID_ARGUMENT;
 352
 353         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 354
 355         device = vlist_find(&devices, devname, device, node);
 356         if (!device)
 357                 return UBUS_STATUS_UNKNOWN_ERROR;
 358
 359         hotplug_call_mount("add", device->name, NULL, NULL);
 360
 361         return 0;
 362 }
 363
 364 struct blockd_umount_context {
 365         struct ubus_context *ctx;
 366         struct ubus_request_data req;
 367 };
 368
 369 static void blockd_umount_hotplug_cb(struct uloop_process *p, int stat)
 370 {
 371         struct hotplug_context *hctx = container_of(p, struct hotplug_context, process);
 372         struct blockd_umount_context *c = hctx->priv;
 373
 374         ubus_complete_deferred_request(c->ctx, &c->req, 0);
 375
 376         free(c);
 377         free(hctx);
 378 }
 379
 380 static int blockd_umount(struct ubus_context *ctx, struct ubus_object *obj,
 381                          struct ubus_request_data *req, const char *method,
 382                          struct blob_attr *msg)
 383 {
 384         struct blob_attr *data[__MOUNT_MAX];
 385         struct blockd_umount_context *c;
 386         char *devname;
 387         int err;
 388
 389         blobmsg_parse(mount_policy, __MOUNT_MAX, data, blob_data(msg), blob_len(msg));
 390
 391         if (!data[MOUNT_DEVICE])
 392                 return UBUS_STATUS_INVALID_ARGUMENT;
 393
 394         devname = blobmsg_get_string(data[MOUNT_DEVICE]);
 395
 396         c = calloc(1, sizeof(*c));
 397         if (!c)
 398                 return UBUS_STATUS_UNKNOWN_ERROR;
 399
 400         c->ctx = ctx;
 401         ubus_defer_request(ctx, req, &c->req);
 402
 403         err = hotplug_call_mount("remove", devname, blockd_umount_hotplug_cb, c);
 404         if (err) {
 405                 free(c);
 406                 return UBUS_STATUS_UNKNOWN_ERROR;
 407         }
 408
 409         return 0;
 410 }
 411
 412 static void block_info_dump(struct blob_buf *b, struct device *device)
 413 {
 414         struct blob_attr *v;
 415         char *mp;
 416         int rem;
 417
 418         blob_for_each_attr(v, device->msg, rem)
 419                 blobmsg_add_blob(b, v);
 420
 421         mp = _find_mount_point(device->name);
 422         if (mp) {
 423                 blobmsg_add_string(b, "mount", mp);
 424                 free(mp);
 425         } else if (device->autofs && device->target) {
 426                 blobmsg_add_string(b, "mount", device->target);
 427         }
 428 }
 429
 430 static int
 431 block_info(struct ubus_context *ctx, struct ubus_object *obj,
 432            struct ubus_request_data *req, const char *method,
 433            struct blob_attr *msg)
 434 {
 435         struct blob_attr *data[__INFO_MAX];
 436         struct device *device = NULL;
 437
 438         blobmsg_parse(info_policy, __INFO_MAX, data, blob_data(msg), blob_len(msg));
 439
 440         if (data[INFO_DEVICE]) {
 441                 device = vlist_find(&devices, blobmsg_get_string(data[INFO_DEVICE]), device, node);
 442                 if (!device)
 443                         return UBUS_STATUS_INVALID_ARGUMENT;
 444         }
 445
 446         blob_buf_init(&bb, 0);
 447         if (device) {
 448                 block_info_dump(&bb, device);
 449         } else {
 450                 void *a;
 451
 452                 a = blobmsg_open_array(&bb, "devices");
 453                 vlist_for_each_element(&devices, device, node) {
 454                         void *t;
 455
 456                         t = blobmsg_open_table(&bb, "");
 457                         block_info_dump(&bb, device);
 458                         blobmsg_close_table(&bb, t);
 459                 }
 460                 blobmsg_close_array(&bb, a);
 461         }
 462         ubus_send_reply(ctx, req, bb.head);
 463
 464         return 0;
 465 }
 466
 467 static const struct ubus_method block_methods[] = {
 468         UBUS_METHOD("hotplug", block_hotplug, mount_policy),
 469         UBUS_METHOD("mount", blockd_mount, mount_policy),
 470         UBUS_METHOD("umount", blockd_umount, mount_policy),
 471         UBUS_METHOD("info", block_info, info_policy),
 472 };
 473
 474 static struct ubus_object_type block_object_type =
 475         UBUS_OBJECT_TYPE("block", block_methods);
 476
 477 static struct ubus_object block_object = {
 478         .name = "block",
 479         .type = &block_object_type,
 480         .methods = block_methods,
 481         .n_methods = ARRAY_SIZE(block_methods),
 482 };
 483
 484 static void
 485 ubus_connect_handler(struct ubus_context *ctx)
 486 {
 487         int ret;
 488
 489         ret = ubus_add_object(ctx, &block_object);
 490         if (ret)
 491                 fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
 492 }
 493
 494 static int autofs_umount(void)
 495 {
 496         umount2(AUTOFS_MOUNT_PATH, MNT_DETACH);
 497         return 0;
 498 }
 499
 500 static void autofs_read_handler(struct uloop_fd *u, unsigned int events)
 501 {
 502         union autofs_v5_packet_union pktu;
 503         const struct autofs_v5_packet *pkt;
 504         int cmd = AUTOFS_IOC_READY;
 505         struct stat st;
 506
 507         while (read(u->fd, &pktu, sizeof(pktu)) == -1) {
 508                 if (errno != EINTR)
 509                         return;
 510                 continue;
 511         }
 512
 513         if (pktu.hdr.type != autofs_ptype_missing_indirect) {
 514                 ULOG_ERR("unknown packet type %d\n", pktu.hdr.type);
 515                 return;
 516         }
 517
 518         pkt = &pktu.missing_indirect;
 519         ULOG_ERR("kernel is requesting a mount -> %s\n", pkt->name);
 520         if (lstat(pkt->name, &st) == -1)
 521                 if (block("autofs", "add", (char *)pkt->name))
 522                         cmd = AUTOFS_IOC_FAIL;
 523
 524         if (ioctl(fd_autofs_write, cmd, pkt->wait_queue_token) < 0)
 525                 ULOG_ERR("failed to report back to kernel\n");
 526 }
 527
 528 static void autofs_expire(struct uloop_timeout *t)
 529 {
 530         struct autofs_packet_expire pkt;
 531
 532         while (ioctl(fd_autofs_write, AUTOFS_IOC_EXPIRE, &pkt) == 0)
 533                 block("autofs", "remove", pkt.name);
 534
 535         uloop_timeout_set(t, AUTOFS_EXPIRE_TIMER);
 536 }
 537
 538 struct uloop_timeout autofs_expire_timer = {
 539         .cb = autofs_expire,
 540 };
 541
 542 static int autofs_mount(void)
 543 {
 544         int autofs_timeout = AUTOFS_TIMEOUT;
 545         int kproto_version;
 546         int pipefd[2];
 547         char source[64];
 548         char opts[64];
 549
 550         if (pipe(pipefd) < 0) {
 551                 ULOG_ERR("failed to get kernel pipe\n");
 552                 return -1;
 553         }
 554
 555         snprintf(source, sizeof(source), "mountd(pid%u)", getpid());
 556         snprintf(opts, sizeof(opts), "fd=%d,pgrp=%u,minproto=5,maxproto=5", pipefd[1], (unsigned) getpgrp());
 557         mkdir(AUTOFS_MOUNT_PATH, 0555);
 558         if (mount(source, AUTOFS_MOUNT_PATH, "autofs", 0, opts)) {
 559                 ULOG_ERR("unable to mount autofs on %s\n", AUTOFS_MOUNT_PATH);
 560                 close(pipefd[0]);
 561                 close(pipefd[1]);
 562                 return -1;
 563         }
 564         close(pipefd[1]);
 565         fd_autofs_read.fd = pipefd[0];
 566         fd_autofs_read.cb = autofs_read_handler;
 567         uloop_fd_add(&fd_autofs_read, ULOOP_READ);
 568
 569         fd_autofs_write = open(AUTOFS_MOUNT_PATH, O_RDONLY);
 570         if(fd_autofs_write < 0) {
 571                 autofs_umount();
 572                 ULOG_ERR("failed to open direcory\n");
 573                 return -1;
 574         }
 575
 576         ioctl(fd_autofs_write, AUTOFS_IOC_PROTOVER, &kproto_version);
 577         if (kproto_version != 5) {
 578                 ULOG_ERR("only kernel protocol version 5 is tested. You have %d.\n",
 579                         kproto_version);
 580                 exit(EXIT_FAILURE);
 581         }
 582         if (ioctl(fd_autofs_write, AUTOFS_IOC_SETTIMEOUT, &autofs_timeout))
 583                 ULOG_ERR("failed to set autofs timeout\n");
 584
 585         uloop_timeout_set(&autofs_expire_timer, AUTOFS_EXPIRE_TIMER);
 586
 587         fcntl(fd_autofs_write, F_SETFD, fcntl(fd_autofs_write, F_GETFD) | FD_CLOEXEC);
 588         fcntl(fd_autofs_read.fd, F_SETFD, fcntl(fd_autofs_read.fd, F_GETFD) | FD_CLOEXEC);
 589
 590         return 0;
 591 }
 592
 593 static void blockd_startup(struct uloop_timeout *t)
 594 {
 595         block("autofs", "start", NULL);
 596 }
 597
 598 struct uloop_timeout startup = {
 599         .cb = blockd_startup,
 600 };
 601
 602 int main(int argc, char **argv)
 603 {
 604         ulog_open(ULOG_SYSLOG | ULOG_STDIO, LOG_DAEMON, "blockd");
 605         uloop_init();
 606
 607         autofs_mount();
 608
 609         conn.cb = ubus_connect_handler;
 610         ubus_auto_connect(&conn);
 611
 612         uloop_timeout_set(&startup, 1000);
 613
 614         uloop_run();
 615         uloop_done();
 616
 617         autofs_umount();
 618
 619         vlist_flush_all(&devices);
 620
 621         return 0;
 622 }